Split Flow Exhaust Deflector

ABSTRACT

A split flow exhaust deflector for a grass moving machine such as a ZTR mower includes a sheet metal body mounted to a lower surface of a muffler of an internal combustion engine, spaced from the lower surface of the muffler to form a pair of channels through which exhaust gasses from the engine pass from the muffler and substantially outwardly through the pair of channels to a pair of locations adjacent a left side surface and a right side surface of the muffler.

FIELD OF THE INVENTION

This invention relates to grass mowing machines, and specifically toexhaust systems for mowers having rear mounted engines such as zero turnradius (“ZTR”) mowers with independently powered left and right drivewheels controlled with hydrostatic transmissions.

BACKGROUND OF THE INVENTION

Grass mowing machines such as ZTR mowers may have internal combustionengines mounted at the rear of the mower frame or platform behind theoperator seat. ZTR mowers also have at least one independently powereddrive wheel on each side of a frame. Hydrostatic transmissions transmitpower from the engine to each of the left and right drive wheels, eitherin forward or reverse. The pair of hydrostatic transmissions, or dualhydrostatic transmission, may be driven through a belt and pulleyarrangement by the engine crankshaft. The hydrostatic transmission(s)may be mounted to the rear-of the vehicle frame adjacent the engine,under and/or behind the operator seat.

A ZTR mower exhaust system may include one or more exhaust pipesextending from the cylinder head or exhaust manifold. The exhaust systemalso may include a muffler attached to the exhaust pipe(s). Hot exhaustgasses may exit the muffler through openings in the muffler, or througha tail pipe directed downwardly or to the side of the ZTR mower. A platealso may be provided to extend over the muffler openings and may bespaced from the openings sufficiently to direct the exhaust gas streamtoward the side of the ZTR mower.

Additionally, a ZTR mower may have a heat shield to protect persons,objects and the grass surface from the muffler itself and the exhaustgas stream. For example, the heat shield may be a curved sheet metalmember attached to the ZTR mower frame and extending behind andunderneath the muffler.

The heat shield, however, does not prevent grass browning if a ZTR moweris parked for a period of time. This is a result of hot engine coolingair combining with the exhaust stream into a concentrated stream. Theresulting heat load may damage or kill the grass under the muffler andheat shield.

There is a need for a exhaust deflector for a ZTR mower that reduces oreliminates grass browning if it is parked for a period of time. There isa need for a exhaust deflector for a ZTR mower that reduces the heatload on grass under the muffler and heat shield.

SUMMARY OF THE INVENTION

A split flow exhaust deflector for a ZTR mower includes a one-piecesheet metal member attached to a lower portion of a muffler on arear-mounted engine, including a generally horizontal planar lowersurface spaced under the lower portion of the muffler. The member formsa left channel leading to a left side opening, and a right channelleading to a right side opening. The left and right side openings areadjacent a left side surface and a right side surface of the mufflersuch that exhaust gasses from the engine exit openings in the lowerportion of the muffler and the flow splits to pass through left andright channels to the left and right side openings at or adjacent theleft and right side surfaces of the muffler. The split flow exhaustdeflector reduces or eliminates grass browning if a ZTR mower is parked,and reduces the heat load on grass under the muffler and heat shield.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of the underside of a ZTR mower with asplit flow exhaust deflector according to a preferred embodiment of theinvention.

FIG. 2 is a perspective view of a split flow exhaust deflector accordingto a preferred embodiment of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT

In one embodiment shown in FIGS. 1-2, a grass mowing machine such aszero turning radius (“ZTR”) mower 100 may have rear mounted engine 102with one or more exhaust pipes 104 connected to and extending from thecylinder head or exhaust manifold. The ZTR mower may include an oblongor generally box-shaped muffler 106 attached to the exhaust pipe(s) andlocated generally behind and under the rear mounted engine. The mufflermay be a two-part member including a top or upper portion 107 secured toa bottom or lower portion 108. Hot exhaust gasses may exit the mufflerthrough downwardly directed openings 109 in the muffler's bottomportion.

In one embodiment, the ZTR mower may include heat shield 112 extendinggenerally over the rear and bottom of the muffler. Additionally, the ZTRmower may include rear panel 114 attached to the frame and extendingaround the rear of the engine.

In one embodiment, split flow exhaust deflector 110 may be a one-piecesheet metal member attached to bottom or lower portion 108 of muffler106. For example, the split flow exhaust deflector may be aluminizedsteel or similar sheet metal. The split flow exhaust deflector may havea generally horizontal planar lower surface that is spaced under thelower surface of the muffler, and spaced from the downwardly directedopenings, by about 20 mm up to about 50 mm.

In one embodiment, the split flow exhaust deflector may form a first orleft channel 122 leading to a first or left side opening 116, and asecond or right channel 124 leading to a second or right side opening118. The left and right side openings of the split flow exhaustdeflector may be at or, adjacent to (i.e., within about 50 mm) the leftside surface 128 and right side surface 130 of the muffler. The lengthof the split flow exhaust deflector between the left and right openingsmay be substantially the same as, or within about 100 mm of, the widthof the muffler between the left and right side surfaces. Thus, thechannels formed by the split flow exhaust deflector may extendsubstantially across the width of the muffler so that exhaust gasses canexit the channels at or adjacent the left and right side surfaces of themuffler.

In one embodiment, channel 122 may have a shorter length than channel124 of the split flow exhaust deflector. This is because the downwardlydirected openings in the muffler may be positioned substantially closerto one side of the muffler than the other side. For example, the leftchannel may be less than about 100 mm in length and the right channelmay be greater than about 200 mm in length. Each channel may have awidth of at least about 50 mm but preferably less than about 200 mm.

In one embodiment, the split flow exhaust deflector may include acentral portion 126 between the left and right channels. The area of thecentral portion may be substantially similar or larger than the areadefined by the downwardly directed openings in the muffler. For example,the width or diameter of the central portion may be at least about 75mm, which may be greater than the width of each channel.

In one embodiment, flange 120 may be provided around the perimeter ofthe split flow exhaust deflector, including along the edge of eachchannel and the central portion. Threaded fasteners may be insertedthrough openings in the flange to secure the split flow exhaustdeflector to the muffler.

In one embodiment, the split flow exhaust deflector may split theexhaust stream into two streams, and direct each stream outwardly to theleft and right side openings 116, 118 at or adjacent the left and rightside surfaces 128, 130 of the muffler. Once an exhaust stream reachesthe left or right side of the muffler, it can mix with the enginecooling air in a mixing zone. As a result, the mixed air has a lowerconcentrated head load to the ground, and prevents grass browning.

Having described the preferred embodiment, it will become apparent thatvarious modifications can be made without departing from the scope ofthe invention as defined in the accompanying claims.

1. A split flow exhaust deflector, comprising: a one-piece sheet metalmember attached to a lower portion of a muffler on a rear-mounted engineand having a generally horizontal planar lower surface spaced under thelower portion of the muffler, the member forming a left channel leadingto a left side opening, a right channel leading to a right side opening,the left and right side openings adjacent a left side surface and aright side surface of the muffler such that exhaust gasses from theengine exit openings in the lower portion of the muffler and passthrough the left and right channels to the left: and right side openingsat or adjacent the left and right side surfaces of the muffler..
 2. Thesplit flow exhaust deflector of claim 1 wherein the left channel isshorter in length than the right channel.
 3. The Split flow exhaustdeflector of claim 1 wherein the muffler is a two-part member includingthe lower portion secured to an upper portion.
 4. The split flow exhaustdeflector of claim 1 further comprising a wider central portion betweenthe, left and right channels.
 5. The split flow exhaust deflector ofclaim 1 further comprising a heat shield positioned below and rearwardlyof the muffler.
 6. A split flow exhaust'deflector, comprising: a pair ofchannels under a muffler, the pair of channels being unequal in length;a central portion between the pair of channels and positioned under aplurality of exhaust openings in a muffler; each channel having a sideopening adjacent a side surface of the muffler.
 7. The split flowexhaust deflector of claim 6 wherein the central portion has an areasubstantially the same as an area defined by the exhaust openings in themuffler.
 8. The split flow exhaust deflector of claim .6 furthercomprising a flange along each of the pair of channels and fastenerssecuring the flange to the muffler.
 9. The split flow exhaust deflectorof claim 6 wherein the width of each channel is less than the width ofthe central portion.
 10. The split flow exhaust deflector of claim 6wherein the split flow exhaust deflector is a one-piece sheet metalbody.
 11. A split flow exhaust deflector, comprising: a sheet metal bodymounted to a lower surface of a muffler connected to an internalcombustion engine of a zero turn radius mower, and spaced from the lowersurface of the muffler to form a pair of channels between the sheetmetal body and the lower surface of the muffler through which exhaustgasses from the engine-pass from'the muffler and substantially outwardlythrough the-pair of channels to a pair of locations adjacent a left sidesurface and a right side surface of the muffler.
 12. The split flowexhaust deflector of claim 11 wherein the sheet metal body includes acentral portion mounted over a plurality of exhaust openings in thelower surface of the muffler.
 13. The split flow exhaust deflector ofclaim 11 wherein the muffler is generally box-shaped.
 14. The split flowexhaust deflector of claim 11 wherein the muffler is connected to theinternal combustion engine by at least one exhaust pipe.